Recent advances in micro-CT machines have made it possible to image with a resolution of <10 m. Scans take ~6 to 20 minutes to acquire, and current iodine contrast agents due to their short half-lives are not generally suitable. We recentl commercialized non-toxic gold X-ray contrast agent, AuroVist, but they are lot more expensive than iodine agents and their whole body clearance is very slow. We now propose biodegradable polymeric contrast agents that are composed of FDA approved components: hyaluronic acid or polylactide/polyglycolide and a derivative of iodine agent Iobitridol that are lot cheaper than our gold-based contrast agents and more absorptive than conventional iodine agents. The new agents can be labeled with additional contrast agents, such as gadolinium or iron oxide, enabling multimodal imaging or double contrasting with dual-beam/dual-detector CT. When labeled with iodine agents and targeting molecules will enable in vivo visualization of organ function, angiogenesis, repair, tumor formation, metastasis, studies of response to drugs and other therapies or conditions, such as ischemia or radiation, and basic biological studies of animals including development, infection, immune response, cardiac studies, tissue injury and healing. The new contrast agents will provide more than four times the radiodensity as compared to the conventional iodine contrast agents and will enable longer imaging times as they are intravascular. These agents will more accurately identify vulnerable plaque by clearly identifying lipid core volume as a percentage of plaque volume, angiogenesis/inflammation, and stenoses, among other risk factors. In addition, their higher radiodensity will enable better imaging of obese patients, reduce radiation dose in normal sized patients and reduce nephrotoxicity to permit use in kidney compromised patients. These capabilities go beyond what other agents offer and if clinically implemented could, through screening, reduce the prevalence of coronary artery disease deaths.